JIACRUROUS DECAPODA OF THE SUDANESE RED SEA. 379 



Crinitus-obeso-manus group. 



Alpheus microstylus, S/>. Bate, 1888, p. 566, pi. 101. fig-. 6. 



A. microstylus, Coutiere, 1905, p. 884, pi. 76. fig. 23. 

 A. microstylus, De Man, 1911 b, p. 344. 



Locality. Section V. E, 2 <? , 20 and 22 mm. 



Distribution. Previously recorded from the Red Sea by Coutiere from 

 Djibouti and Mascat ; widely distributed in the Pacific Ocean. 



Crinitus-crinitus group. 



Alpheus alcyone, De Man, 1902, p. 870, Taf. 27. fig. 61. 



A. ahyone, Nobili, 1906 5, p. 32. 



A. aculeipes. Coutiere, 1905, p. 892, pi. 79. fig. 31. 



A. ahyone, De Man, 1911 b, p. 351. 



Locality. Station V. 0, one specimen, 10 mm. 



Distribution. Previously recorded from the Red Sea by Coutiere from 

 Djibouti ; widely distributed in the Indian Ocean. 



Alpheus sp. ? 



Locality. Station V. A, 1 J 1 , 10 mm. 



Remarks. This specimen approaches A. alcyone very closely, but differs 

 from it mainly in the fact that the median rostral process is absent or obsolete 

 so that the rostrum presents the form of an emarginate plate. 



The dactylus of the last three pairs of legs has a very small accessory 

 tooth so that it is obscurely bi-unguiculate, There is no prominent spine 

 on the distal corner of the lower margin of the carpus of the third legs, but 

 there are two spines on the median portion of this margin. The second 

 joint of the carpus of the second pair of legs is about three times as long as 

 the first. The other characters are exactly as in A. alcyone. 



Alpheus bucephaloides, Nobili, 1905 l>, p. 238. 



A. bucephaloides, Nobili, 1006 b, p. 29. 



Localities. Station V. E, 1 <? , 9 mm. Station IX. A, 1 <^ , 10 mm. 



Remarks. It is with a considerable amount of reserve that I refer these 

 specimens to Nobili's species. They differ from the latter in not having the 

 movable finger of the small cheliped broadened and fringed with seta;, anil 

 in having the second joint of the carpus of the second legs 1*3 times as long 

 as the first, instead of 1*6 as in A. bucephaloides. 



The carpus of the third legs has only three spinules on the lower border in 

 addition to the terminal one and has no spines on the upper border. There 



9C)» 



